What is smear preparation?
The first step in most bacterial staining procedures is the preparation of a smear. In a smear preparation, cells from a culture are spread in a thin film over a small area of a microscope slide, dried, and then fixed to the slide by heating or other chemical fixatives.
What is a smear in Gram stain?
A small amount is spread in a very thin layer on a glass slide. This is called a smear. A series of stains are added to the sample. A lab team member examines the stained smear under the microscope, looking for bacteria. The color, size, and shape of the cells help identify the specific type of bacteria.
What is bacterial smear preparation and staining?
The preparation of a smear is required for many laboratory procedures, including the Gram-stain. The purpose of making a smear is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure. A smear can be prepared from a solid or broth medium.
What is Gram stain preparation?
DIRECTIONS
- Apply a smear of bacteria on to a slide.
- Add about 5 drops of Hucker’s Crystal Violet to the culture.
- Add about 5 drops of iodine solution to the culture.
- Tilt slide and decolorize with solvent (acetone-alcohol solution) until purple color stops running.
- Add about 5 drops of Safranine O.
What is smear in microbiology?
A bacterial smear is a thin layer of bacteria placed on a glass blade and «fixed» by heat or other, partly to ensure that they remain attached to the glass, for coloring. It can be prepared from a solid medium or broth. Then a coloring is applied.
What are the two types of smear preparation?
Four different types of smear preparation methods (conventional method, blood film method, drop and rest method, and water-wash method) were carried out according to the standard reference as described below.
How do you prepare a smear for staining?
Culture from solid media: Using a sterile pipette, add one drop of sterile saline or sterile water to the center of the microscope slide. Aseptically pick a small amount of an isolated colony with a loop and gently mix into the drop of sterile saline or water using circular motions. Mix evenly to make a thin smear.
What is the purpose of Gram staining?
A Gram stain is most often used to find out if you have a bacterial infection. If you do, the test will show if your infection is Gram-positive or Gram-negative. A Gram stain may also be used to diagnose fungal infections.
Is smear and stain same?
Because bacteria are, for the most part, transparent, we use stains to give them color for microscopic observation. Making a bacterial smear prepares the bacteria to be stained and a simple stain is a quick and easy way to observe bacteria.
What are the three types of stained smear preparation?
Stains
- Smear Preparation.
- Simple Stain.
- Negative Stain.
- Gram Stain.
- Congo Red Capsule Stain.
- Wirtz’s Endospore Stain.
What is Gram staining in microbiology?
Gram staining is a common technique used to differentiate two large groups of bacteria based on their different cell wall constituents. The Gram stain procedure distinguishes between Gram positive and Gram negative groups by coloring these cells red or violet.
What are the 4 steps of Gram staining?
The performance of the Gram Stain on any sample requires 4 basic steps that include applying a primary stain (crystal violet) to a heat-fixed smear, followed by the addition of a mordant (Gram’s Iodine), rapid decolorization with alcohol, acetone, or a mixture of alcohol and acetone and lastly, counterstaining with …